1. Technical Field
This disclosure relates generally to the field of nutritional compositions, such as infant formulas, human milk fortifiers, children's dietary supplements, and the like, having lactoferrin, in particular lactoferrin produced by a non-human source. More particularly, the disclosure relates to a method of inhibiting the adhesion of at least one pathogen in a human gastrointestinal tract by administering to the human a nutritional composition including lactoferrin produced by a non-human source.
2. Background
There are currently a variety of dietary compositions for humans, especially young humans, to provide supplemental or primary nutrition at certain stages in life. Generally, commercial dietary compositions for infants seek to mimic to the extent possible the composition and associated functionality of human milk. Through a combination of proteins, some of which have physiological activity, and blended fat ingredients, dietary compositions are formulated such that they simulate human milk for use as a complete or partial substitute. Other ingredients often utilized in dietary compositions for infants may include a carbohydrate source such as lactose as well as other vitamins, minerals and elements believed to be present in human milk for the absorption by the infant.
Lactoferrin is one of the primary proteins in human milk and is considered a glycoprotein having an average molecular weight of approximately 80 kilodaltons. It is an iron binding protein having the capacity to bind two molecules of iron in a reversible fashion and can facilitate the uptake of iron within the intestines for the human. Functionally, lactoferrin regulates iron absorption and as such can bind iron-based free radicals as well as donate iron for an immunological response.
An additional role of lactoferrin is its anti-microbial activity in guarding against intestinal infections in humans generally, but especially in infants. Lactoferrin has been known to be both bacteriostatic and bactericidal in inhibiting the growth of specific bacteria while also killing microbes prior to a successful invasion of intestinal cells.
In obtaining a commercially viable dietary composition, the addition of lactoferrin has generally been limited due to predicted losses of activity during processing. For example, generally, the temperature and pH requirements in processing infant formulas and other products such as human milk fortifiers and various children's products reduce specific functions of the lactoferrin, causing lactoferrin not to be included within a final formulation. In addition, lactoferrin is often considered only for its iron binding qualities; thus, lactoferrin may generally be excluded from a formulation where such properties are thought to be diminished by processing conditions.
Further, as known in the art, human breast milk is relatively low in iron, containing about 0.3 milligrams of iron per liter of breast milk. While this quantity is low, human infants have high absorption rate, absorbing about half of the iron from the breast milk. However, when human infants are given prior art formulas with high levels of iron fortification, for example, of from about 10 mg to about 12 milligrams per liter, the infants absorb less than about 5% of the total iron. With such increased levels of iron within the prior art formulas, virtually all of the lactoferrin iron binding sites would be expected to be occupied, as lactoferrin is a known iron transport protein.
Additional complications of the prior art formulas include the inability of providing a bacteriostatic effect. This is partially due to the use of lactoferrin with blocked or damaged binding sites, as the bacteriostatic effect is at least partially related to the degree of binding to iron of the lactoferrin present within the formula.
Accordingly, it would be beneficial to provide a nutritional composition, such as an infant formula, human milk fortifier, children's dietary supplement, and the like, which contains lactoferrin, in particular, lactoferrin produced by a non-human source. Preferably, the lactoferrin included in the compositions has a bacteriostatic effect even after processing under conditions of high temperature and low pH.